Fluorescent dyes and non-fluorescent ligands are excellent affinity tags that can be recognized by labeled primary antibodies, providing an alternative to the traditional signal amplification as well as expanding the number of targets detected in multiplex experiments. Applications where anti-dye antibodies have been successfully used include DNA hybridization, immunohistochemistry, flow cytometry, ELISA, and western blotting. Their high specificity also makes them ideal reagents in applications where the signal detection is more difficult due to increased background (for example, non-specific detection of endogenous biotin in cells and tissue).